The invention relates to a method and an arrangement for the production of composite work pieces comprising layers laminated to each other, with at least one of the layers being a glass plate.
The primary application of the present invention is the lamination of photo-voltaic modules, in which a planar arrangement of solar cells is covered by a glass plate at the front and is encapsulated by a rear film or in a similarly weather-proof and primarily moisture-tight fashion. Furthermore, at least one adhesive layer with a thermally reactive adhesive material is included, which is activated by the effects of heat.
An arrangement of the present type comprises a lamination press for laminating the composite work pieces under the effects of pressure and heat as well as at least one curing station positioned downstream in reference to the lamination press and/or at least one cooling station for curing and/or cooling the composite work pieces. Both, the curing station, if provided, as well as the cooling station are usually embodied as presses with heating and/or cooling plates.
One example for a lamination press that can be used in a method and an arrangement of the present type is known from WO 2006/128699 A2. Here, above a heating plate an upper part, which can be moved upwards and downwards, is arranged with a sealing frame, which circumscribes a vacuum chamber. When closing the press, the upper part moves onto the heating plate and the sealing frame is placed onto the heating plate in a sealing fashion such that the vacuum chamber can be evacuated. A flexible membrane is stretched over the sealing frame, sealing the vacuum chamber and serving as a compression member in order to apply the pressure against the heating plate necessary for the lamination of the work piece arranged on the heating plate. For this purpose, when the press is closed, the volume located underneath the membrane and between said membrane and the heating plate is evacuated such that the membrane tightly contacts the work piece.
Therefore, due to the evacuation of the volume positioned underneath, the membrane applies the necessary pressure for the lamination process onto the work piece, while simultaneously the evacuation of the work piece environment ensures that during the heating of the work piece no bubbles form therein or that they can be extracted. Accordingly, the lamination process can be performed entirely inside the lamination press so that subsequently only a cooling station must be passed; however it is also possible to perform the lamination process under a vacuum in the lamination press only until the adhesive material in the adhesive layer has been activated, then to open the lamination press and to further treat the work piece thermally in a subsequent curing station under normal pressure.
When now photo-voltaic modules or other composite work pieces with glass plates are laminated in a lamination press with a compression member it frequently happens that the glass plate (or at least one of several glass plates) breaks. Although the shards of the broken glass plate, due to the lamination process, still contact the adhesive layer with its activated adhesive material it is still not only possible but actually occurs regularly that shards or chips fall off and cause major problems in the subsequent processing steps, thus particularly in the curing station and/or the cooling station, damaging in particular additional composite work pieces during the curing and/or cooling process.